The long-term of the study is to further elucidate the genetic basis of aortic aneurysms. One objective is to determine the incidence and mode of inheritance of familial thoracic and abdominal aneurysms. Another objective is to discover the genetic basis of familial aortic aneurysms. Fibroblasts from skin biopsies will be used to study the synthesis, secretion and processing of type III collagen and fibrillin, connective tissue proteins that provide tensile strength to the aortic wall.